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Should we reconsider all-polyethylene tibial implants in total knee replacement?
S D Muller1, D J Deehan, J P Holland
1Department of Orthopaedics, Freeman Hospital, Freeman Road, High Heaton, Newcastle upon Tyne, UK. s.d.muller@ncl.ac.uk
The Journal of Bone and Joint Surgery. British Volume
|December 13, 2006
Summary
In total knee replacement, all-polyethylene tibial implants showed no difference in migration or clinical outcomes compared to metal-backed designs over 24 months. This suggests comparable performance for uncomplicated primary procedures.
Area of Science:
- Orthopedic Surgery
- Biomedical Engineering
- Clinical Trials
Background:
- The optimal design for tibial components in total knee replacement (TKR) remains under investigation.
- Modular tibial implants offer design flexibility, but their comparative performance requires further definition.
Purpose of the Study:
- To compare the in vivo migration and clinical outcomes of all-polyethylene versus metal-backed tibial implants in PFC-Sigma TKR.
- To evaluate the functional performance of these two tibial implant designs over a 24-month period.
Main Methods:
- A prospective, randomized controlled trial involving 51 patients undergoing primary TKR.
- Radiostereophotogrammetric analysis (RSA) was used to assess implant migration.
- Clinical outcomes were evaluated using SF-12 and Oxford knee scores, alignment, and range of motion.
Main Results:
- No statistically significant difference in tibial implant migration between all-polyethylene and metal-backed designs at 24 months.
- One metal-backed implant showed migration exceeding 1 mm; no all-polyethylene implants reached this threshold.
- Both groups demonstrated significant improvements in SF-12 and Oxford knee scores post-operation.
Conclusions:
- In uncomplicated primary TKR, the all-polyethylene PFC-Sigma tibial prosthesis demonstrates comparable migration and clinical outcomes to its metal-backed counterpart.
- The study suggests equivalent short-term performance between the two tibial implant designs, although clinical outcome measures were not statistically powered.